Serratella

Serratellas are not a major hatch on western fly waters, but they can be locally important. They are in the crawler group of mayflies. The nymphs inhabit medium to fast water.

Hatches can begin in July and continue through September. At emergence, nymphs rise to the surface and the dun emerges on the water. Trout may prefer to take the nymphs as they rise, rather than the duns. So observe the hatch carefully and experiment to see what the trout are focused on: rising nymphs, emergers and cripples, or duns.

Spinner falls are in the evening, but are seldom important. If you encounter one you can match it with a Rusty Spinner or similar pattern.